export declare const MIN_SOURCE_TEXT_CHARS = 2000;
export declare const MIN_RETAINED_RATIO = 0.5;
export declare function visibleTextLength(html: string): number;
export declare function extractionAdvisory(opts: {
    html: string;
    extractedTextLength: number;
}): string | undefined;
export declare function withAdvisory(markdown: string, advisory: string | undefined): string;